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Cos10°cos50°cos70°=√3/8 |
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Answer» Answer: The answer for this question is = ( COS 10 cos 50 )cos 70 = 1/2 (2cos10cos50) cos 70 = 1/2 (cos 60+cos 40) cos 70 WKT value of cos 60 is 1/2 . put the value in NEXT STEP =1/2 (1/2 + cos 40) cos 70 = 1/2 ( cos 70/2 +cos 70 cos 40) = 1/2 ( cos 70+cos 70 cos 40/2) = 1/4 (cos 70 + 2 cos 70 cos 40) = 1/4 (cos 70 + cos 110+ cos 30) = 1/4 ( cos 70+ cos 180-70 + cos 30) = 1/4 (cos 70- cos 70 + cos 30) = 1/4 * √3/2 = √3/8 hence PROVED Step-by-step explanation: Hope this answer help u!!!!! byee |
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